CN109085049A - COD detection method in a kind of sewage and recycled water - Google Patents
COD detection method in a kind of sewage and recycled water Download PDFInfo
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Abstract
The invention discloses COD detection methods in a kind of sewage and recycled water, detection mechanism of the invention, water sampling amount, oxidant dosage are identical as HJ 828-2017 method, using manganese sulfate, copper sulphate, aluminum aluminum sulfate, etc. the metal ion sulfate of 4 kinds of different catalytically actives and selectivity substitute noble silver reagent；Using the reduction of mixture of sulfuric phosphoric acid acidity, the presence of the adsorptivity of phosphoric acid and potassium chromium sulfate, weaken potassium dichromate oxidation, and using large volume closing resolution, shortens digestion time to 25min, realize the mercuryless interference for preventing chloride ion；Increase reaction pressure simultaneously, improve solution digestion condition to 165 DEG C, improves oxidation efficiency；Resolution/titration bottle integration, the titration of golden composite electrode potential substitute manual indicator titration, calculate the COD in water sample.5 metal ion species sulfate are nontoxic in the present invention, are easy to get, inexpensively, and mixture of sulfuric phosphoric acid large volume closing resolution sample adaptability is good, and COD result is consistent with HJ 828-2017 method, and the quick measurement for realizing COD is measured with green.
Description
Technical field
It is the present invention relates to chemical analysis technology field, in particular to a kind of by without silver-colored mercury-free-sealed micro-pressure Catalytic digestion,
The constant-current titration of gold indicator electrode detects COD detection method in sewage and recycled water indirectly.
Background technique
COD (Chemical-Oxygen-Demand), abbreviation COD refer to molten in water body under certain conditions
The mass concentration of solution property substance oxygen corresponding with strong oxidizer potassium bichromate consumed by suspended matter, in terms of mg/L.It is table
Show the overall target of reducing substances in water body.COD in water body is excessively high, shows that organic pollution is very seriously, to destroy ring
Border and biocenological balance, cause water body to deteriorate.Therefore, COD is an important parameter of sewage treatment plant, and environmental protection
One important indicator of monitoring.
The standard method of COD mainly has 3 kinds using more in domestic measurement water at present, chromium method titration (HJ
828-2017 substitutes GB11914-1989), chromium method rapid-digestion spectrophotometry (HJ/T399-2007), and acidity Gao Meng
Sour potassium method (GB11892-1989), and the continuous flowing spectrophotometry based on first three methods principle；First two method according to
According to principle it is almost the same, with potassium bichromate solution High-temperature Digestion oxidation water in reducing substances, be chiefly used in trade effluent, life
The water analysis of sewage etc..Permanganimetric method fado is for measuring underground water and compared with the aerobic magnitude of clean water sample.It is other also to wrap
Include a certain domain-specific GB/T 15456-2008 " measurement of COD in industrial circulating water ", GB/T 22597-2008
" measurement of COD in recycled water ", " the measurement potassium iodide alkalinity of chemical oxygen demand of high-chloride wastewater is high by HJ/T 132-2003
Potassium manganate method " HJ/T 70-2001 " the measurement chlorine correction method of chemical oxygen demand of high-chloride wastewater ".Due to the chemical oxygen demand of water sample
Amount, by the type and concentration of addition oxidant, the acidity of reaction solution, reaction temperature and the presence or absence of time and catalyst and
Different Results are obtained, therefore COD is also a conditionity index.
Wherein, chromium method titration (HJ 828-2017) is the main method of the current COD monitoring in China, also referred to as CODCrMethod,
It is equal with ISO 6060 " measurement of water chemical oxygen demand ", this method oxygenation efficiency is high, and reproducibility is good, accurately and reliably, becomes state
The universally recognized classical standard method of border society, and at present in China's water COD determination referee method, be applicable in COD
Value is greater than the water sample of 16mg/L, and the determination of the upper limit to not diluted water sample is 700mg/L.It is not suitable for chloride concentration to be greater than
The brackish water of 1000mg/L (after dilution).Its measuring principle are as follows: in sulfuric acid medium, using potassium bichromate as oxidant, sulphur
Sour silver is catalyst, and mercuric sulfate is the screening agent of chloride ion, and resolution reaction solution acidity of sulfuric acid is 9.2mol/L, and heating keeps resolution anti-
Liquid is answered to boil, 148 DEG C ± 2 DEG C of boiling temperature is digestion condition.Reaction response 2h is heated with cooling for reflux, digestion solution is naturally cold
But after, using ferroin as indicator, remaining potassium bichromate is titrated with l ferrous ammonium sulfate solution, according to l ferrous ammonium sulfate solution
Consumption calculate water sample COD value.
However, the shortcomings that this classical standard method is also fairly obvious, it is mainly reflected in, (1) need to be heated to reflux 2h and make
Analysis time is too long, and water consumption power consumption；(2) reagent dosage is big, and the usage amount of sulfuric acid and silver sulfate is larger, and using expensive
Ag2SO4Lead to analysis cost height as catalyst；(3) Toxic mercury salt complexing masking chloride ion, unprocessed direct row is added
It puts, has not only caused the loss of a large amount of noble metal, but also serious secondary pollution is caused to environment water, and the mercury salt in waste liquid is difficult
Processing；(4) interference of chlorine, when the mass concentration of chloride ion in waste water is high and COD value is low, potassium dichromate method measurement COD seems
It is unable to do what one wishes, the reason is that Chloride Ion In Water and oxidant, catalyst reaction, make measurement result generate relatively large deviation.
Based on the improvement of chromium method titration (HJ 828-2017), the research that many scholars at home and abroad are done is mainly reflected in
Improve digestion procedure, change reagent and improves three aspects of means of testing.Closed Catalytic digestion method and the opening of standard method are returned
Stream resolution principle is consistent, and 1978, Best.D.G et al. cleared up water sample using confined reaction device earliest, and experiment is effectively
It inhibits the volatilization of organic matter and avoids the interference of Cl-, this subsequent method is widely used in practical measurement.Bai Ying et al. reference
BS ISO 15705-2003(Water quality-Determination ofthe chemical oxygen demand
Index (ST-COD)-Small-scale sealed-tube method), " measurement (ST-COD) of water chemical oxygen demand is small
Type seals tube method ", digestion time shortens, while the waste liquid amount generated is only the 1/10 of standard chlorine method COD, reduces continuous mode
Bring secondary pollution.The corresponding Cerium-group REE of small size sealed digestion, sampling amount are few compared with chromium method titration, sample representativeness
There is limitation, and water sample muddiness error is big；It is again easy when overpressure is excessive when High-temperature Digestion if increasing sampling amount and amount of reagent
It causes bumping or collapse to splash even bottle and splits phenomenon.Change reagent, in terms of catalyst, mainly one or two kinds of mistakes cheap and easy to get
Cross metal sulfate or oxide substitution noble silver reagent has in a certain range as shown in the closely related document of the present invention
Preferable consistency, but in the COD testing result of part actual sample, still there is large error with noble silver reagent.It is eliminating
In terms of chloride ion interference, acidity method is mainly decreased slightly as using mixture of sulfuric phosphoric acid, silver salt inhibits method, Cl2Absorption process, interference deduction method,
Calibration curve method plus Cr3+Method, HCl removal method are with bismuth salt removal method etc..Means of testing is improved in addition to volumetric method and photometry, base
Consistent in chromium method titration (HJ 828-2017), there are also potentiometric titrations and coulometric titration, the Pt electricity that only document provides
There is surface passivation phenomenon in pole in practical applications, influences long period use；
Bottle, mainly small size closing resolution, resolution/colorimetric one, mating luminosity are cleared up in closing reported in the literature at present
Method uses；As described in document A9, B9.Large volume closes minute-pressure resolution (sampling amount identical as HJ828-2017 method and amount of reagent)
And corresponding safeguard has not been reported；
Remaining potassium bichromate constant-current titration uses platinum electrode in current digestion solution reported in the literature, uses for a long time
There is passivation phenomenon, electrode response is slack-off.
With the closely related document of the present invention:
A Yang Yang, gold revitalize .MnSO4-CuSO4The Journal of Liaoning Institute of Technology research of composite catalyst Rapid Determination of COD
.2007,25 (5): 316-318,321. full text, with MnSO4-CuSO4Composite catalyst replaces in standard potassium dichromate method
Ag2SO4, the sulfuric acid in standard potassium dichromate method is replaced with H2SO4-H3PO4 nitration mixture, digestion condition is 165 DEG C, and digestion time is
15min, spectrophotometry measure COD content
B poplar winter jasmine, Zhang Li, Ye Xiaodong improve potassium dichromate method and quickly measure water sample CODcr. Chengdu Information Technology Institute
Journal .2005,21 (2): 273-276. full text proposes the catalyst for changing redox reaction in CODcr measurement, with
MnSO4Instead of Ag2SO4, in H2SO4-H3PO4Is measured in mixed acid solution
C father-in-law kerria, thank dawn plum quickly, mercury-free open pipe measurement waste water in chemical oxygen demand quantifier elimination journal of Zhejiang university (agriculture
Industry and life science version) .2003,29 (2): 216-219. full text is medium in sulfuric-phosphoric, and potassium bichromate is oxidant, sulphur
Sour silver makees catalyst, silver nitrate and potassium chromium sulfate sample to be digested in teat glass, is disappeared under conditions of chloride ion screening agent
Remaining bichromate titration or spectrophotometry measure after solution
Quick measurement environmental science of the COD without mercury salt and management .2005,30 (6) in D Liu Wen, Wang Mei water:
110-219. full text, is co-catalyst with ammonium molybdate, aluminum aluminum sulfate, reduces the dosage of catalyst sulfuric acid silver, uses silver nitrate solution
Instead of mercuric sulfate removal Chloride Ion In Water interference, the pollution of mercury salt is avoided.
The bright .CuSO of E Chang Zhixian, Tao Ying, Zhang Ling, Li De4Do the discussion analytical chemistry of COD in catalyst measurement waste water
.2009,37 (z1): B165. full text, uses CuSO4It is COD in catalyst measurement waste water, compared with standard method of analysis, the party
The error of method is within the allowable range.
F Wei Xiao Ling, Gong Qi, Lv Hengyi, He great Peng quickly learn by pollution-free measurement waste water COD cr technique study Guangxi University
Report (natural science edition) .2006,31 (4): 309-31, full text, this method shorten the reaction time using micro-wave digestion；Use sulfuric acid
The mixture of copper and manganese sulfate is as catalyst；Use H2SO4-H3PO4 nitration mixture as reaction medium；Use bismuth nitrate as chloride ion
Screening agent
, the macro micro-wave digestion-automatic potential titrator tests of Chen Zhi determine the Guangdong COD chemical industry in waste water to G leaf tree
.2009,36 (7): full text, by " sulfuric acid-potassium bichromate-aluminum aluminum sulfate-ammonium molybdate " system, using micro-wave digestion, automatic electric
COD in the titrator measurement waste water of position.
A kind of method of fast slaking chemical oxygen demand in water quality testing in photometric analysis of H CN 1004919871972C.
.2009-05-27. full text is with copper sulphate-manganese sulfate substitution silver sulfate, open closed resolution, and luminosity colorimetric is suitble to low chlorine water
Matter COD analysis.
I CN 1598548A. is without mercury salt chemical oxygen demand of high-chloride wastewater CODCrRapid assay methods .2005-03-23.
It in full, is that silver sulfate is substituted by nickel sulfate-manganese sulfate, silver nitrate-potassium chromium sulfate substitutes mercuric sulfate, open closed resolution, hand
Work indicator method measures the COD in water sample
106932532 A. of J CN is a kind of for detecting the analysis .2017-07-07. full text of COD in water, is
Normal capacity chromium method CODCrOptimization, pass through increase silver sulfate catalytic amount, shorten digestion time
105259296 B. of K CN is applied to the catalyst and chemical oxygen demand weight testing method of COD test
.2017.11.10. full text, is normal capacity chromium method CODCrImprovement, catalyst is made using potassium acid sulfate and potassium sulfate, realize
The green measurement of CODCr
Sample digestion method .2011.06.29. full text in a kind of COD determination of 102109433 B. of L CN, belongs to
Normal capacity chromium method CODCrImprovement, using manganese sulfate and cerous sulfate make catalyst substitution silver nitrate, mercuric sulfate is according to water sample chlorine
Ionic size is added, and shortens digestion time to 30min.
However the above-mentioned documents water sample scope of application has certain limitation.
Summary of the invention
It is an object of the invention to overcome the deficiencies of the prior art and provide the detection sides COD in a kind of sewage and recycled water
Method, to solve the problems such as return time is too long in the prior art, reagent dosage is big, the loss of a large amount of noble metal.
The present invention is achieved by the following technical solutions:
The present invention provides COD detection method in a kind of sewage and recycled water, method includes the following steps:
(1) 10mL homogeneous water sample is drawn in resolution/titration integrated bottle, and it is mixed to sequentially add complex reagent, oxidant and sulphur phosphorus
Then acid screws the lid of the integrated bottle；
The complex reagent is specifically made of manganese sulfate, copper sulphate, aluminum aluminum sulfate, potassium chromium sulfate, and mass ratio is 3~1:
3~1:1:1；The complex reagent additional amount is 0.4~0.7g；
The oxidant is specially potassium bichromate, and concentration is 0.05mol/L~0.1mol/L, and additional amount is specially
10mL；
The mixture of sulfuric phosphoric acid is specially the sulfuric acid and phosphoric acid of 5~3:1 of volume ratio, and additional amount is 13~17mL；
(2) the resulting integrated bottle of step 1 is placed under 165 ± 3 DEG C of environment and carries out airtight digestion while carrying out air-cooled time
It flows, is taken out after 25~30min；
(3) step 2 gained integrated bottle is cooled to room temperature, then with the lid and inner wall of a small amount of distilled water shower integrated bottle
Its interior overall solution volume is set to reach 70~80mL；
(4) step 3 gained integrated bottle is placed on titration platform, with 0.1mol/L iron ammonium sulfate standard solution and compound
Relevant parameter, starting drop is arranged in remaining potassium bichromate in solution in gold electrode constant-current titration step 3 integrated bottle before titrating
It is fixed, terminal is sentenced certainly；
(5) blank test simultaneously is converted into COD value, completes test.
Further, integrated bottle described in step 1 is specifically made of the cylindrical bottle body of lid and top end opening, the bottle body
Top bottleneck is smooth and has screw thread, 2~3mm of the bottle body wall thickness, and highly 150~170mm, 40~45mm of internal diameter are marked with
The scale of 10mL meter.
Further, the lid is specifically made of polytetrafluoroethyllining lining cone elastomer.
Further, being specially by the device that the integrated bottle is heated to 165 ± 3 DEG C in step 2 can air-cooled timing temperature adjustment
Digestion device, the bottom of the digestion device offer multiple heating traps for being used to place the integrated bottle, also set in the digestion device
It is equipped with air cooling equipment, is additionally provided with control device on the digestion device.
Further, the heating well depth is 45~50mm, and integrated bottle described in step 2 is put into after the heating trap it
Interior liquid level is lower than the heating trap tip height.
Further, the height for the cooling airflow least significant end that the air cooling equipment generates is higher than the heating trap tip height.
Further, the outside of the heating trap is also covered with explosion-proof transparent glass.
Further, the composite catalyst additional amount is 0.5g.
Further, the mixture of sulfuric phosphoric acid is specially 15mL.
The present invention has the advantage that compared with prior art
1, the present invention forms complex reagent, benefit using the metal ion sulfate of a variety of different catalytically actives and selectivity
With the adsorptivity of phosphoric acid, increase reaction pressure, promotion reaction temperature is achieved and urged with silver sulfate to improve oxidation efficiency
The close catalytic effect of agent solves the problems, such as noble silver reagent cost height and recycles difficulty, substitutes the more of argentum reagent
Metal ion species sulfate is easy to get inexpensive.
2, the present invention is suitably reduced acidity and trivalent chromium by mixture of sulfuric phosphoric acid, can subtracted using large volume closing resolution
Weak potassium dichromate oxidation, and form [CrCl2]+, while shortening digestion time, collaboration prevents the interference of chloride ion, substitutes toxic
The open closed resolution mode of sulfuric acid mercury reagent achievees the effect that the elimination chloride ion interference of similar mercuric sulfate.
3, the present invention devises the resolution/titration integrated bottle of cylinder containing lid, sampling amount and reagent dosage in experimentation
It is consistent with HJ828-2017 method, when solving large volume High-temperature Digestion pressure of the inside of a bottle it is excessive may cause collapse to splash and burst apart and ask
Topic.
4, manual indicator titration of the present invention using gold electrode constant-current titration substitution HJ 828-2017 method, measurement
Process automation, titration error is smaller, also eliminates platinum electrode in digestion solution for a long time using the electrode passivation phenomenon occurred.?
It is obtained and the consistent result of HJ 828-2017 method in tested sample COD analysis.
Detailed description of the invention
Fig. 1 is the structural schematic diagram of integrated bottle and digestion device in the present invention.
Specific embodiment
It elaborates below to the embodiment of the present invention, the present embodiment carries out under the premise of the technical scheme of the present invention
Implement, the detailed implementation method and specific operation process are given, but protection scope of the present invention is not limited to following implementation
Example.
" water and effluent monitoring analysis method guide (first volume) " points out the potassium dichromate method oxidation butanone 2h of HJ828-2017
When oxygenation efficiency be 78.7%.Therefore choosing butanone is test substance, and mercury-free through the invention is without silver-colored sealed digestion method to fourth
The comparison of the oxygenation efficiency of ketone, to judge the oxidability of sealed digestion method, the results showed that 25min or so is under the conditions of 165 ± 3 DEG C
It can reach similar resolution effect, oxygenation efficiency 79.0%, 25~30min of digestion time is advisable；Mixture of sulfuric phosphoric acid volume ratio 5:1~
When 3:1,13~17mL of dosage is advisable；In mixture of sulfuric phosphoric acid-potassium dichromate oxidation system, potassium bichromate concentration with 0.05mol/L~
0.1mol/L is advisable；Complex reagent manganese sulfate: copper sulphate: aluminum aluminum sulfate: when potassium chromium sulfate mass ratio 3:3:1:1~1:1:1:1,
Dosage is that 0.4~0.7g is advisable；As a result same HJ828-2017 is calculated.
That is COD=C × (V1- V2)×8000/V(mg/L).In formula: C --- the concentration of iron ammonium sulfate standard solution,
mol/L；V1--- the volume of iron ammonium sulfate normal concentration, mL when titration blank；V2--- iron ammonium sulfate mark when Titration Water Sample
The volume of quasi- solution, mL；The volume of V --- water sample, mL；8000 --- oxygen (1/4) molal weight, changing as unit of mg/L
Calculation value；COD --- COD, mg/L.
As devised in Fig. 1 present invention containing cover cylindrical resolution/titration integrated bottle and can air-cooled timing temperature adjustment digestion device
3.Specifically be made of the cylindrical bottle body 2 of lid 1 and top end opening in resolution/titration integrated bottle, 2 top bottleneck of bottle body it is smooth and
There are screw thread, bottle body 2~3mm of wall thickness, height 150~170mm, 40~45mm of internal diameter are marked with the scale of 10mL meter, digestion device 3
Bottom offer it is multiple for placing the heating traps 4 of integrated bottle, can effectively to integrated bottle be placed on the part in heating trap 4 into
Row heats, and is additionally provided with air cooling equipment 5 in digestion device, control device 6 is additionally provided on digestion device, settable by control device 6
The operating parameter of equipment, heating well depth is 45~50mm, and integrated bottle is put into its interior liquid level after heating trap and is lower than heating
Trap tip height, the outside for heating trap are also covered with explosion-proof transparent glass 7, are partially carried out using air cooling equipment 5 on bottleneck and liquid
Air blast cooling makes the slightly boiled reflux of digestion solution, to solve large volume, namely by the sampling of surrogate's target HJ828-2017 method
Amount and reagent dosage, when High-temperature Digestion pressure of the inside of a bottle it is excessive may cause collapse problem of splashing and burst apart.
Below by specific embodiment, technical solution of the present invention is described in further detail in conjunction with Figure of description:
Embodiment 1
Refine oil peace and quiet be lauched.Advanced line blank test, parameter input formula.Special homemade large volume sealed digestion/
It titrates in integrated bottle, water sample 10mL, the sulfuric acid and phosphatase 11 4mL that volume ratio is 3:1, the manganese sulfate-of mass ratio 3:1:1:1 is added
Copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.4g, 0.05mol/L potassium bichromate 10mL closes micro- reflux resolution, 162 DEG C of holdings
30min makes 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly uses gold combination electrode current potential
Titration is detected, automatic to show the relevant informations such as result；Measuring the peace and quiet COD (COD) that is lauched of oil refining is
32.2mg/L。
Embodiment 2
Saliferous level-one clarifies water.Water sample 10mL, the sulfuric acid and phosphatase 11 5mL that volume ratio is 4:1, mass ratio 3:1:1:1 are
Manganese sulfate-copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.5g, 0.05mol/L potassium bichromate 10mL closes micro- reflux resolution,
163 DEG C of holding 30min make 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly multiple with gold
Composite electrode potentiometric titration is detected, automatic to show the relevant informations such as result；Saliferous level-one clarifying basin water chemistry oxygen demand
It (COD) is 220mg/L.
Embodiment 3
It polymerize sewage.Water sample 10mL, the sulfuric acid and phosphatase 11 7mL that volume ratio is 3:1, mass ratio 3:1:1:1 are manganese sulfate-
Copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.6g, 0.05mol/L potassium bichromate 10mL closes micro- reflux resolution, 165 DEG C of holdings
28min makes 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly uses gold combination electrode current potential
Titration is detected, automatic to show the relevant informations such as result；Polymerizeing sewage chemical oxygen demand (COD) is 63.8mg/L.
Embodiment 4
Outlet monitors water.Water sample 10mL, the sulfuric acid and phosphatase 11 5mL that volume ratio is 5:1, mass ratio 1:2:1:1 are sulfuric acid
Manganese-copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.5g, 0.1mol/L potassium bichromate 10mL closes micro- reflux resolution, 164 DEG C of guarantors
25min is held, makes 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly with gold combination electrode electricity
Position titration is detected, automatic to show the relevant informations such as result；It is 1130mg/ that outlet, which monitors water COD (COD),
L。
Embodiment 5
Chemical fertilizer sewage containing ammonia.Water sample 10mL, the sulfuric acid and phosphatase 11 5mL that volume ratio is 3:1, mass ratio 3:3:1:1 are sulfuric acid
Manganese-copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.7g, 0.05mol/L potassium bichromate 10mL closes micro- reflux and clears up, and 166 DEG C
25min is kept, makes 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly uses gold combination electrode
Potentiometric titration is detected, automatic to show the relevant informations such as result, and measuring chemical fertilizer COD of sewage containing ammonia is 22.7mg/L.
Embodiment 6
Thermoelectrochemistry sewage.Water sample 10mL, the sulfuric acid and phosphatase 11 5mL that volume ratio is 3:1, mass ratio 3:3:1:1 are sulfuric acid
Manganese-copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.4g, 0.05mol/L potassium bichromate 10mL closes micro- reflux and clears up, and 167 DEG C
26min is kept, makes 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly uses gold combination electrode
Potentiometric titration is detected, automatic to show the relevant informations such as result, and measuring thermoelectrochemistry COD of sewage is 11.5mg/L.
Embodiment 7
Sanitary sewage.Water sample 10mL, the sulfuric acid and phosphatase 11 5mL that volume ratio is 3:1, mass ratio 3:3:1:1 are manganese sulfate-
Copper sulphate-aluminum aluminum sulfate-potassium chromium sulfate 0.7g, 0.05mol/L potassium bichromate 10mL closes micro- reflux resolution, 168 DEG C of holdings
25min makes 70~80mL of total volume with a small amount of distilled water shower lid and inner wall after cooling, directly uses gold combination electrode current potential
Titration is detected, automatic to show the relevant informations such as result, and measuring sanitary sewage COD is 133mg/L.
Embodiment 8
According to the method described above successively to nitrile dirt B461 waste water, reuse pool, the import of sewage conditioning tank, spinning recycling sewage,
Oil Tank oily wastewater, wastewater equalization pond, chemical fertilizer cyanogens-containing sewage water, coked waste water etc. are sampled test
Comparative test, test result such as table one are done to embodiment 1-8 using 828 method of HJ.
1 present invention of table is compared with HJ828 methods and results
Table 1
Seen from table 1, whole COD data tested by the present invention are coincide with HJ828 methods and results, and accuracy is consistent, does not have
There is the tolerance beyond two methods and results.
Embodiment 9
A variety of test objects are chosen, method of the invention, national standard method HJ828- are used to each subjects
2017 and control document A~document L method and step carry out COD test, test result such as table 2.
The present invention of table 2 compared with the actual water sample COD result of 828 method of HJ and documents/(mg/L)
Table 2
Method of the invention acquirement and HJ in tested sample COD analysis as can be seen from Table 2
The completely the same result of 828-2017 method (error is in 828 method allowed band of HJ), and document A~text
Offer L can only in tested sample COD result part it is consistent, some total result has exceeded the permission of 828 method of HJ
Error range.
So-called allowable error referred to and is worth on the basis of 828 method COD of HJ, the error range of two methods and results, substantially
- 10%~+10% and low to contain when -5%~+5% and middle content COD (50~500mg/L) when high COD (>=500mg/L)
It is -15%~+15% when measuring COD (≤50mg/L).
The above enumerated are only specific embodiments of the present invention for finally, it should also be noted that.Obviously, the present invention is unlimited
It, can also there are many applications for needing pre-treatment sample to measure in above embodiments.Those skilled in the art can be from this
All deformations that disclosure of invention is directly exported or associated, are considered as protection scope of the present invention.
Claims (9)
1. COD detection method in a kind of sewage and recycled water, which is characterized in that method includes the following steps:
(1) 10mL homogeneous water sample is drawn in resolution/titration integrated bottle, sequentially adds complex reagent, oxidant and mixture of sulfuric phosphoric acid,
Then the lid of the integrated bottle is screwed；
The complex reagent is specifically made of manganese sulfate, copper sulphate, aluminum aluminum sulfate, potassium chromium sulfate, mass ratio be 3~1:3~
1:1:1；The complex reagent additional amount is 0.4~0.7g；
The oxidant is specially potassium bichromate, and concentration is 0.05mol/L~0.1mol/L, and additional amount is specially 10mL；Institute
The sulfuric acid and phosphoric acid that mixture of sulfuric phosphoric acid is specially 5~3:1 of volume ratio are stated, additional amount is 13~17mL；
(2) the resulting integrated bottle of step 1 is placed under 165 ± 3 DEG C of environment and carries out airtight digestion while carrying out air-cooled reflux, 25
It is taken out after~30min；
(3) step 2 gained integrated bottle is cooled to room temperature, then makes it with the lid and inner wall of a small amount of distilled water shower integrated bottle
Interior overall solution volume reaches 70~80mL；
(4) step 3 gained integrated bottle is placed on titration platform, with 0.1mol/L iron ammonium sulfate standard solution and golden composite
Relevant parameter is arranged in remaining potassium bichromate in solution in 3 integrated bottle of electrode potential titration step before titrating, starting titrates, from
Sentence terminal；
(5) blank test simultaneously is converted into COD value, completes test.
2. COD detection method in a kind of sewage according to claim 1 and recycled water, which is characterized in that described in step 1
Integrated bottle is specifically made of the cylindrical bottle body of lid and top end opening, and bottle body top bottleneck is smooth and has screw thread, described
Bottle body 2~3mm of wall thickness, height 150~170mm, 40~45mm of internal diameter, is marked with the scale of 10mL meter.
3. COD detection method in a kind of sewage according to claim 2 and recycled water, which is characterized in that the lid tool
Body is made of polytetrafluoroethyllining lining cone elastomer.
4. COD detection method in a kind of sewage according to claim 1 and recycled water, which is characterized in that by institute in step 2
State integrated bottle be heated to 165 ± 3 DEG C device be specially can air-cooled timing temperature adjustment digestion device, the bottom of the digestion device opens up
There are multiple heating traps for being used to place the integrated bottle, air cooling equipment is additionally provided in the digestion device, is gone back on the digestion device
Equipped with control device.
5. COD detection method in a kind of sewage according to claim 4 and recycled water, which is characterized in that the heating trap
Depth is 45~50mm, and integrated bottle described in step 2 is put into its interior liquid level after the heating trap and is lower than the heating trap
Tip height.
6. COD detection method in a kind of sewage according to claim 5 and recycled water, which is characterized in that the air-cooled dress
The height for setting the cooling airflow least significant end of generation is higher than the heating trap tip height.
7. COD detection method in a kind of sewage according to claim 6 and recycled water, which is characterized in that the heating trap
Outside be also covered with explosion-proof transparent glass.
8. COD detection method in a kind of sewage according to claim 1 and recycled water, which is characterized in that described compound to urge
Agent additional amount is 0.5g.
9. COD detection method in a kind of sewage according to claim 1 and recycled water, which is characterized in that the sulphur phosphorus is mixed
Acid-specific is 15mL.
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| CN110118738A (en) * | 2019-05-14 | 2019-08-13 | 同济大学 | A kind of preparation and application method of water chemical oxygen demand detection agent |
| CN110208258A (en) * | 2019-06-19 | 2019-09-06 | 沈阳理工大学 | Catalytic digestion column and its preparation method, CODCrRapid determination device and its make method |
| CN110261534A (en) * | 2019-07-15 | 2019-09-20 | 江苏天宇检测技术有限公司 | A kind of sea water COD detection method |
| CN110487765A (en) * | 2019-08-30 | 2019-11-22 | 广州睿宜精测环保科技有限公司 | A kind of COD rapid detection method of rare-earth fluorescent probe as prefabricated reagent |
| CN112611832A (en) * | 2020-12-25 | 2021-04-06 | 河北旋盈环境检测服务有限公司 | Method for detecting chemical oxygen demand of water quality |
| CN114018905A (en) * | 2021-09-28 | 2022-02-08 | 神美科技有限公司 | Kit for rapidly detecting water quality COD (chemical oxygen demand), preparation method and use method thereof |
| CN114199798A (en) * | 2021-11-12 | 2022-03-18 | 葛洲坝水务温岭有限公司 | Method for rapidly measuring high-range COD |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110118738A (en) * | 2019-05-14 | 2019-08-13 | 同济大学 | A kind of preparation and application method of water chemical oxygen demand detection agent |
| CN110118738B (en) * | 2019-05-14 | 2020-04-17 | 同济大学 | Preparation and use method of water quality chemical oxygen demand detection agent |
| CN110208258A (en) * | 2019-06-19 | 2019-09-06 | 沈阳理工大学 | Catalytic digestion column and its preparation method, CODCrRapid determination device and its make method |
| CN110208258B (en) * | 2019-06-19 | 2021-09-24 | 沈阳理工大学 | Catalytic digestion column, preparation method thereof and CODCrRapid measuring apparatus and method of using the same |
| CN110261534A (en) * | 2019-07-15 | 2019-09-20 | 江苏天宇检测技术有限公司 | A kind of sea water COD detection method |
| CN110487765A (en) * | 2019-08-30 | 2019-11-22 | 广州睿宜精测环保科技有限公司 | A kind of COD rapid detection method of rare-earth fluorescent probe as prefabricated reagent |
| CN112611832A (en) * | 2020-12-25 | 2021-04-06 | 河北旋盈环境检测服务有限公司 | Method for detecting chemical oxygen demand of water quality |
| CN112611832B (en) * | 2020-12-25 | 2022-06-14 | 河北旋盈环境检测服务有限公司 | Method for detecting chemical oxygen demand of water quality |
| CN114018905A (en) * | 2021-09-28 | 2022-02-08 | 神美科技有限公司 | Kit for rapidly detecting water quality COD (chemical oxygen demand), preparation method and use method thereof |
| CN114199798A (en) * | 2021-11-12 | 2022-03-18 | 葛洲坝水务温岭有限公司 | Method for rapidly measuring high-range COD |
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Application publication date: 20181225 |